CN212364701U

CN212364701U - Optical imaging system, image capturing module, electronic device and mobile device

Info

Publication number: CN212364701U
Application number: CN202022058149.9U
Authority: CN
Inventors: 蔡雄宇; 兰宾利; 周芮; 赵迪
Original assignee: Tianjin OFilm Opto Electronics Co Ltd
Current assignee: Jiangxi Oufei Optics Co ltd
Priority date: 2020-09-18
Filing date: 2020-09-18
Publication date: 2021-01-15
Anticipated expiration: 2030-09-18

Abstract

The present application provides an optical imaging system, sequentially comprising from an object side to an image side: a first lens element having a negative refractive power, the object-side surface being convex; the second lens with negative bending force, the object side surface and the image side surface are both concave surfaces; a third lens element with positive refractive power having a convex object-side surface; a fourth lens having a positive refracting power; a fifth lens having a positive refracting power; the sixth lens has negative bending force, and the fifth lens and the sixth lens have positive bending force integrally; the seventh lens with positive bending force, the object side surface and the image side surface are convex surfaces; the optical imaging system further comprises a diaphragm; the optical imaging system satisfies the following conditional expression: 6< f56/f < 10; where f56 is the combined focal length of the fifth lens and the sixth lens, and f is the focal length of the optical imaging system. The optical imaging system can also have better imaging capability in a dark environment. The application also provides an image capturing module with the optical imaging system, an electronic device with the image capturing module and a mobile device with the image capturing module.

Description

Optical imaging system, image capturing module, electronic device and mobile device

Technical Field

The utility model relates to an optical imaging technical field, in particular to optical imaging system, get for instance module, electron device and mobile device.

Background

At present, in the 3C electronic product and the automobile field of making a video recording, the consumer has all proposed higher requirement to the imaging quality and the volume size of making a video recording the module. On a cell phone, consumers want to get a larger field of view without occupying a larger volume. With the increasing requirements of the automobile field on road traffic safety and automobile safety, and the rise of the look-around camera, the driving assistance system and the unmanned driving market, the vehicle-mounted lens is more and more applied to the automobile driving assistance system. Meanwhile, due to the diversification of the use environment, people also put forward higher requirements on the imaging quality of the camera module under different ambient light conditions, the comfort level of pictures and the like.

In the process of implementing the present application, the inventor finds that at least the following problems exist in the prior art: the current optical camera module is generally difficult to realize possessing good imaging quality in the environment with darker light such as night, tunnel, underground parking lot, mine hole. Especially when light brightness changes, the module of making a video recording can't realize the focus altogether, and then leads to the formation of image effect unsatisfactory.

SUMMERY OF THE UTILITY MODEL

In view of the above, it is desirable to provide an optical imaging system with day and night confocal and an image capturing module, an electronic device and a mobile device having the optical imaging system to solve the above problems.

An embodiment of the present application provides an optical imaging system, sequentially from an object side to an image side, comprising:

the lens comprises a first lens with negative bending force, wherein the object side surface of the first lens is a convex surface;

the second lens is provided with negative bending force, and the object side surface and the image side surface of the second lens are both concave surfaces;

a third lens element with positive refractive power, the object-side surface of the third lens element being convex;

a fourth lens having a positive refracting power;

a fifth lens having a positive refracting power;

a sixth lens having a negative bending force, and the fifth lens and the sixth lens have a positive bending force as a whole; and

the fourth lens is provided with a convex object side surface and a convex image side surface;

the optical imaging system further comprises a diaphragm, and the diaphragm is arranged on the object side of the fifth lens;

the optical imaging system satisfies the following conditional expression:

6<f56/f<10；

wherein f56 is a combined focal length of the fifth lens and the sixth lens, and f is a focal length of the optical imaging system.

In the optical imaging system of the embodiment of the application, the reasonable bending force configuration of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens meets the requirement of the optical imaging system on day-night confocal imaging, so that the optical imaging system can have better imaging capability in dark environments such as night, tunnel, mine tunnel and underground parking lot.

The optical imaging system can correct the aberration of the system by limiting the combined focal length of the fifth lens and the sixth lens, and the accumulated tolerance of the two elements is set to the tolerance of an integrated element by the combined structure of the fifth lens and the sixth lens, so that the eccentric sensitivity can be reduced, the system assembly sensitivity can be reduced, the problems of lens process manufacturing and lens assembly can be solved, and the yield can be improved. Through aberration correction between the fifth lens and the sixth lens, the imaging resolution is favorably improved. Exceeding the conditional limit range of the combined focal length of the fifth lens and the sixth lens is detrimental to the correction of aberrations of the optical imaging system, resulting in a reduction in imaging quality.

In some embodiments, an image-side surface of the fifth lens is cemented with an object-side surface of the sixth lens;

the object side surface and the image side surface of the fifth lens are convex surfaces;

the object side surface of the sixth lens is a concave surface, and the image side surface of the sixth lens is a convex surface.

It can be understood that the fifth lens element and the sixth lens element have positive refractive power as a whole, and the cemented surface of the fifth lens element and the sixth lens element protrudes to the image side, which is helpful for improving the resolution of the optical imaging system.

In some embodiments, the optical imaging system further comprises a stop disposed between the fourth lens and the fifth lens.

The optical imaging system is provided with the diaphragm to reduce stray light, and is beneficial to improving the image quality.

In some embodiments, the operating band of the optical imaging system comprises 0.4 μm to 1 μm.

The application range of the optical imaging system simultaneously comprises visible light and infrared light, and infrared light imaging is favorable for improving the imaging capability of the optical imaging system in a dark environment of visible light and improving the imaging quality.

In some embodiments, the optical imaging system satisfies the following conditional expression:

4<f7/f<7；

wherein f7 is the focal length of the seventh lens, and f is the focal length of the optical imaging system.

The seventh lens provides positive bending force for the system, and the emergent angle of the ray bundle can be shrunk by meeting the conditional expression, so that the angle of the chief ray of the ray bundle entering the photosensitive element is favorably reduced, the photosensitive performance of the photosensitive element is improved, and the imaging resolution is improved. Exceeding the conditional range is not favorable for correcting the aberration of the optical imaging system, thereby reducing the imaging quality.

-7<f1/CT1<-3；

wherein f1 is the focal length of the first lens, and CT1 is the thickness of the first lens on the optical axis.

The change of the central thickness of the first lens can affect the focal length of the optical imaging system, and the relation between the central thickness of the first lens and the focal length of the optical imaging system is reasonably matched by meeting the limitation of the conditional expression, so that the tolerance sensitivity of the central thickness of the first lens can be reduced, the difficulty of the processing technology of the single lens is reduced, the assembly yield of the lens group is favorably improved, and the production cost is further reduced. When the upper limit of the conditional expression is exceeded, the bending force of the first lens is too strong, the system is easy to generate astigmatism which is difficult to correct, and the imaging quality of the imaging system is reduced; when the optical imaging system exceeds the conditional lower limit, the bending force of the first lens is insufficient, so that the large-angle light rays are not favorably emitted into the system, and the wide angle of the optical imaging system is not favorably realized.

-8<R3/CT2<-2；

wherein R3 is a radius of curvature of the object-side surface of the second lens element at the optical axis, and CT2 is a thickness of the second lens element at the optical axis.

The second lens is a negative lens and can further diffuse light because the second lens is of a double-concave structure. By satisfying the limitation of the conditional expression, the deviation of the incident angle and the emergent angle of the light rays of different view fields can be reduced, thereby reducing the sensitivity; the processing difficulty can be reduced and the thickness tolerance sensitivity can be reduced by adjusting the thickness of the second lens, and the yield is improved. When the limit of the conditional expression is exceeded, it is not favorable to correct the deviation and reduce the sensitivity.

-12<f23/f<-6；

wherein f23 is a combined focal length of the second lens and the third lens, and f is a focal length of the optical imaging system.

The second lens and the third lens with different bending forces are combined into a lens group, the combined focal length is limited, the negative bending force is enabled to be integrally formed through the limitation of the conditional expression, the aberration of the light beam at the edge of the first lens is favorably corrected, and the image resolving power is improved. When the limit of the conditional expression is exceeded, aberration control is not proper, resulting in a decrease in imaging quality.

1.5<TTL/EPL<3.5；

wherein, TTL is a distance on the optical axis from the object-side surface of the first lens element to the image plane, and EPL is a distance on the optical axis from the stop to the image plane.

By satisfying the conditional expression, the light rays are incident on the photosensitive element in a manner close to vertical incidence, so that the optical imaging system has telecentric characteristics, which are very important for the light sensing capability of the solid-state electronic photosensitive element, the light sensing sensitivity of the electronic photosensitive element can be improved, and the possibility of generating dark angles by the system can be reduced. When the optical imaging system exceeds the conditional lower limit, the total length of the optical imaging system (namely the distance from the object side surface of the first lens to the imaging surface on the optical axis) is not limited, and the system is not miniaturized; when the upper limit of the conditional expression is exceeded, the improvement of the brightness of the imaging surface of the optical imaging system is not facilitated, and the farther the distance from the diaphragm to the imaging surface is, the more easily the optical imaging system generates a dark angle, and the improvement of the imaging quality is not facilitated.

In some embodiments, at least one lens in the optical imaging system satisfies the following conditional expression:

1/(n486-n950)≤30；

wherein n486 is a refractive index corresponding to the at least one lens when the working wavelength is 486nm, and n950 is a refractive index corresponding to the at least one lens when the working wavelength is 950 nm.

By satisfying the conditional expression, the chromatic aberration correction of the optical imaging system at the visible light wave band and the near infrared wave band is facilitated, and the reduced defocusing change is further facilitated when the optical imaging system is suitable under the visible light environment and is suitable when the optical imaging system is switched to the near infrared wave band. When the constraint of the conditional expression is exceeded, the optical imaging system generates a large defocus variation when used in two environments, and generates imaging blur in a certain environment, so that the resolution is reduced.

vdi≤25；

wherein vdi is an abbe number of the at least one lens.

A certain lens in the optical imaging system meets the conditional expression, chromatic aberration is corrected favorably, and color saturation of the optical imaging system during imaging is improved.

3.5<Imgh/epd≤5.2；

where Imgh is an image height corresponding to the maximum field angle of the optical imaging system, and epd is an entrance pupil diameter of the optical imaging system.

By satisfying the conditional expression, the improvement of the image surface brightness during the imaging of the large target surface is favorably ensured. When the upper limit of the conditional expression is exceeded, the diameter of the entrance pupil of the optical imaging system is smaller, the width of a light beam emitted by the optical imaging system is reduced, and the improvement of the image surface brightness is not facilitated; when the lower limit of the conditional expression is exceeded, the image plane area of the optical imaging system is small, and the field angle range of the optical imaging system is narrowed.

1mm^-1<tan(1/2*FOV)/f＜3mm^-1；

wherein FOV is the maximum field angle of the optical imaging system, and f is the focal length of the optical imaging system.

By limiting the condition, the control of the distortion of the edge field of view of the large-angle optical imaging system is facilitated, the image plane deformation is avoided, and the discrimination precision of the system is improved. When the limit of the conditional expression is exceeded, the edge distortion control of the optical imaging system in large-angle imaging is not facilitated, and the imaging quality is reduced.

The embodiment of the utility model provides a get for instance module, including above-mentioned arbitrary embodiment optical imaging system and photosensitive element, photosensitive element set up in optical imaging system's image side.

The utility model discloses get for instance the module and include optical imaging system, optical imaging system is through the configuration reasonable to the crooked power of inner lens to the combination focus scope of fifth lens and sixth lens has been injectd, has satisfied getting for instance the confocal demand of formation of image of module pair day night. Get for instance the module and still realized in darker environment such as night, tunnel, mine hole, underground parking garage through optical imaging system, also can have better imaging ability.

An embodiment of the utility model provides an electronic device, include: the casing with the module of getting for instance of above-mentioned embodiment, get for instance the module and install on the casing.

The utility model discloses electronic device can promote optical imaging system's formation of image quality including getting for the image module, through the configuration of reasonable zigzag power, has realized electronic device to the confocal demand of formation of image of day night, makes it in the darker environment of light such as night, tunnel, mine hole, underground parking garage, also can have better formation of image ability.

An embodiment of the utility model provides a mobile device, include: the image capturing module comprises a body and the image capturing module of the embodiment, wherein the image capturing module is arranged on the body.

The utility model discloses mobile device can promote optical imaging system's formation of image quality including getting for the image module, through the configuration of reasonable zigzag power, has realized the mobile device to the confocal demand of formation of image of day night, makes it in the darker environment of light such as night, tunnel, mine hole, underground parking garage, also can have better formation of image ability.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

fig. 1 is a schematic structural diagram of an optical imaging system according to a first embodiment of the present invention.

Fig. 2 is a schematic view of spherical aberration (mm), astigmatism (mm), and distortion (%) of the optical imaging system according to the first embodiment of the present invention.

Fig. 3 is a schematic structural diagram of an optical imaging system according to a second embodiment of the present invention.

Fig. 4 is a schematic view of spherical aberration (mm), astigmatism (mm), and distortion (%) of an optical imaging system according to a second embodiment of the present invention.

Fig. 5 is a schematic structural diagram of an optical imaging system according to a third embodiment of the present invention.

Fig. 6 is a schematic view of spherical aberration (mm), astigmatism (mm), and distortion (%) of an optical imaging system according to a third embodiment of the present invention.

Fig. 7 is a schematic structural diagram of an optical imaging system according to a fourth embodiment of the present invention.

Fig. 8 is a schematic view of spherical aberration (mm), astigmatism (mm), and distortion (%) of an optical imaging system according to a fourth embodiment of the present invention.

Fig. 9 is a schematic structural diagram of an optical imaging system according to a fifth embodiment of the present invention.

Fig. 10 is a schematic view of spherical aberration (mm), astigmatism (mm), and distortion (%) of an optical imaging system according to a fifth embodiment of the present invention.

Fig. 11 is a schematic structural diagram of an image capturing module according to an embodiment of the present invention.

Fig. 12 is a schematic structural diagram of an electronic device according to an embodiment of the present invention.

Fig. 13 is a schematic structural diagram of a mobile device according to an embodiment of the present invention.

Description of the main elements

Image capturing module 100

Optical imaging system 10

First lens L1

Second lens L2

Third lens L3

Fourth lens L4

Fifth lens L5

Sixth lens L6

Seventh lens L7

Cover glass L8

Stop STO

Object sides S1, S3, S5, S7, S9, S11, S13, S15

Like sides S2, S4, S6, S8, S10, S12, S14, S16

Image plane S17

Photosensitive element 20

Electronic device 200

Case 210

Mobile device 300

Body 310

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and to simplify the description, but do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the present invention. Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", may explicitly or implicitly include one or more of the described features. In the description of the present invention, "a plurality" means two or more unless specifically limited otherwise.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; may be mechanically connected, may be electrically connected or may be in communication with each other; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

In the present disclosure, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may comprise direct contact between the first and second features, or may comprise contact between the first and second features not directly. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly above and obliquely above the second feature, or simply meaning that the first feature is at a lesser level than the second feature.

The following disclosure provides many different embodiments or examples for implementing different features of the invention. In order to simplify the disclosure of the present invention, the components and arrangements of specific examples are described below. Of course, they are merely examples and are not intended to limit the present invention. Furthermore, the present invention may repeat reference numerals and/or reference letters in the various examples, which have been repeated for purposes of simplicity and clarity and do not in themselves dictate a relationship between the various embodiments and/or arrangements discussed. In addition, the present disclosure provides examples of various specific processes and materials, but one of ordinary skill in the art may recognize applications of other processes and/or use of other materials.

Referring to fig. 1, an optical imaging system 10 according to an embodiment of the present invention includes, in order from an object side to an image side: a first lens L1 with negative bending force, the object side S1 of the first lens L1 being convex; the second lens L2 with negative bending force, the object-side surface S3 and the image-side surface S4 of the second lens L2 are both concave; a third lens element L3 with positive refractive power, the object-side surface S5 of the third lens element L3 being convex; a fourth lens L4 having a positive bending force; a fifth lens L5 having a positive bending force; the sixth lens L6 with negative bending force, the fifth lens L5 and the sixth lens L6 are of a cemented structure, and the fifth lens L5 and the sixth lens L6 have positive bending force as a whole; the seventh lens element L7 with positive refractive power has convex object-side surface S13 and image-side surface S14 of the seventh lens element L7.

Specifically, the first lens L1 has an object-side surface S1 and an image-side surface S2, the second lens L2 has an object-side surface S3 and an image-side surface S4, the third lens L3 has an object-side surface S5 and an image-side surface S6, the fourth lens L4 has an object-side surface S7 and an image-side surface S8, the fifth lens L5 has an object-side surface S9 and an image-side surface S10, the sixth lens L6 has an object-side surface S11 and an image-side surface S12, and the seventh lens L7 has an object-side surface S13 and an image-side surface S14. The image-side surface S10 of the fifth lens L5 is cemented with the object-side surface S11 of the sixth lens L6.

Further, the optical imaging system 10 further includes a stop STO disposed on the object side of the fifth lens L5. Specifically, the stop STO may be disposed on the object side of the first lens L1, or between the first lens L1 and the second lens L2, or between the second lens L2 and the third lens L3, or between the third lens L3 and the fourth lens L4, or between the fourth lens L4 and the fifth lens L5, and a specific disposition position of the stop STO may be set according to actual needs, which is not limited herein. It is understood that the optical imaging system 10 helps to improve the image quality by providing the stop STO to reduce stray light.

Further, the optical imaging system 10 satisfies the following conditional expression:

6<f56/f<10；

wherein f56 is a combined focal length of the fifth lens L5 and the sixth lens L6, and f is a focal length of the optical imaging system 10.

In the optical imaging system 10 of the embodiment of the application, the reasonable bending force configuration of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6 and the seventh lens L7 meets the requirement of the optical imaging system 10 for day and night confocal imaging, so that the optical imaging system 10 can also have better imaging capability in environments with darker light rays such as night, tunnel, mine cave and underground parking lot.

The optical imaging system 10 can correct the aberration of the system by limiting the combined focal length of the fifth lens L5 and the sixth lens L6, and can reduce the eccentricity sensitivity, reduce the system assembly sensitivity, solve the problems of lens process manufacturing and lens assembly, and improve the yield by setting the tolerance of the two elements to the tolerance of an integrated element through the arrangement of the gluing structure. Through aberration correction between the glued structures, the imaging resolution is favorably improved. Exceeding the conditionally restricted range of the combined focal length of the fifth lens L5 and the sixth lens L6 is detrimental to the correction of aberrations of the optical imaging system 10, resulting in a reduction in imaging quality.

In some embodiments, both the object-side surface S9 and the image-side surface S10 of the fifth lens element L5 are convex;

the object-side surface S11 of the sixth lens element L6 is concave, and the image-side surface S12 is convex.

It can be appreciated that the fifth lens element L5 and the sixth lens element L6 have positive refractive power as a whole, and the cemented surface thereof protrudes to the image side, which contributes to the improvement of the resolution of the optical imaging system 10.

In some embodiments, a stop STO is disposed between the fourth lens L4 and the fifth lens L5, thereby providing a possibility for realization of a large angle of view. Moreover, the central stop STO makes the structure of the optical imaging system 10 in a certain symmetry, so that the optical distortion is well controlled.

In some embodiments, the operating band of the optical imaging system 10 includes 0.4 μm to 1 μm.

The application range of the optical imaging system 10 includes visible light and infrared light at the same time, and infrared light imaging is helpful to improve the imaging capability of the optical imaging system 10 in an environment with dark visible light, and improve the imaging quality.

In some embodiments, the object-side surface S1 of the first lens element L1 is convex and the image-side surface S2 is concave; the object-side surface S3 of the second lens element L2 is concave along the optical axis, and the image-side surface S4 is concave along the optical axis; the object-side surface S5 of the third lens element L3 is convex along the optical axis, and the image-side surface S6 is convex along the optical axis; the object-side surface S7 of the fourth lens element L4 is convex and the image-side surface S8 is concave or planar; the object-side surface S9 of the fifth lens element L5 is convex along the optical axis, and the image-side surface S10 is convex along the optical axis; the object-side surface S11 of the sixth lens element L6 is concave along the optical axis, and the image-side surface S12 is convex along the optical axis; the object-side surface S13 of the seventh lens element L7 is convex along the optical axis, and the image-side surface S14 is convex along the optical axis.

The optical imaging system 10 has a wide field of view through reasonable lens configuration, reduces the size of the optical imaging system 10 while maintaining good optical performance, realizes miniaturization of the optical imaging system 10, and has good day and night confocal capability.

In some embodiments, optical imaging system 10 further includes a cover glass L8, cover glass L8 having an object side S15 and an image side S16. The cover glass L8 is disposed between the image side surface S14 and the image surface S17 of the seventh lens L7. The protective glass L8 is completely transparent and light can directly pass through, and the protective glass L8 is used to protect photosensitive elements and the like outside the optical imaging system 10.

When the optical imaging system 10 is used for imaging, light rays emitted or reflected by a subject enter the optical imaging system 10 from the object side direction, pass through the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7 and the protective glass L8 in sequence, and finally converge on the image plane S17.

In some embodiments, the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, and the protective glass L8 are made of glass.

In some embodiments, the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, and the seventh lens L7 are all spherical mirrors.

In some embodiments, the optical imaging system 10 satisfies the following conditional expressions:

4<f7/f<7；

wherein f7 is the focal length of the seventh lens L7, and f is the focal length of the optical imaging system 10.

The seventh lens L7 provides positive bending force for the system, and through satisfying the conditional expression, the exit angle of collapsible pencil is favorable to reducing the pencil and penetrates into the chief ray angle of photosensitive element, promotes photosensitive element's photosensitive performance, promotes the formation of image resolution. Exceeding the conditional range is not favorable for correcting the aberration of the optical imaging system 10, thereby reducing the imaging quality.

-7<f1/CT1<-3；

wherein f1 is the focal length of the first lens L1, and CT1 is the thickness of the first lens L1 on the optical axis.

The change of the central thickness of the first lens L1 affects the focal length of the optical imaging system 10, and by satisfying the limitation of the conditional expression and reasonably matching the relationship between the central thickness of the first lens L1 and the focal length of the optical imaging system 10, the tolerance sensitivity of the central thickness of the first lens L1 can be reduced, the difficulty of the processing technology of the single lens is reduced, the assembly yield of the lens group is favorably improved, and the production cost is further reduced. When the upper limit of the conditional expression is exceeded, the bending force of the first lens L1 is too strong, so that astigmatism which is difficult to correct is easily generated in the system, and the imaging quality of the system is reduced, and in addition, the larger the central thickness of the first lens L1 is, the larger the weight of the system is, which is not favorable for the light-weight characteristic of the optical imaging system 10; when the conditional lower limit is exceeded, the bending force of the first lens L1 is insufficient, which is not favorable for the large-angle light ray entering system and the wide-angle of the optical imaging system 10.

-8<R3/CT2<-2；

wherein R3 is a radius of curvature of the object-side surface S3 of the second lens L2 on the optical axis, and CT2 is a thickness of the second lens L2 on the optical axis.

Since the second lens L2 is a biconcave lens, the second lens is a negative lens, and can further diffuse light. By satisfying the limitation of the conditional expression, the deviation of the incident angle and the emergent angle of the light rays of different view fields can be reduced, thereby reducing the sensitivity; by adjusting the thickness of the second lens L2, the processing difficulty can be reduced, the sensitivity of thickness tolerance can be reduced, and the yield can be improved. When the limit of the conditional expression is exceeded, it is not favorable to correct the deviation and reduce the sensitivity.

-12<f23/f<-6；

wherein f23 is a combined focal length of the second lens L2 and the third lens L3, and f is a focal length of the optical imaging system 10.

The second lens L2 and the third lens L3 with different bending forces are combined into a lens group, the combined focal length is limited, the negative bending force is provided for the whole lens group by meeting the limitation of the conditional expression, and the aberration of the light beam at the edge of the first lens L1 is corrected to improve the image resolving power. When the limit of the conditional expression is exceeded, aberration control is not proper, resulting in a decrease in imaging quality.

1.5<TTL/EPL<3.5；

wherein, TTL is an axial distance from the object-side surface S1 to the image plane S17 of the first lens element L1, and EPL is an axial distance from the stop STO to the image plane S17.

By satisfying the conditional expressions, the light will be incident on the photosensitive element in a manner close to normal incidence, so that the optical imaging system 10 has a telecentric property, which is very important for the light-sensing capability of the solid-state electronic photosensitive element, and the light-sensing sensitivity of the electronic photosensitive element can be improved, and the possibility of generating a dark angle by the system can be reduced. When the conditional lower limit is exceeded, it is not favorable to limit the total length of the optical imaging system 10 (i.e. the distance from the object-side surface S1 of the first lens L1 to the image surface S17 on the optical axis), and it is not favorable to realize the characteristic of system miniaturization; when the upper limit of the conditional expression is exceeded, the brightness of the image plane S17 of the optical imaging system 10 is not favorably improved, and the farther the distance from the stop STO to the image plane S17 is, the more easily the optical imaging system 10 generates a dark angle, which is not favorable for improving the imaging quality.

In some embodiments, at least one lens in the optical imaging system 10 satisfies the following conditional expression:

1/(n486-n950)≤30；

By satisfying the conditional expressions, the chromatic aberration correction of the optical imaging system 10 in the visible light band and the near infrared band is facilitated, and the optical imaging system 10 is further facilitated to generate reduced defocus variation when being applied in a visible light environment and when being switched to a near infrared band. When the constraint of the conditional expression is exceeded, the optical imaging system 10 generates a large defocus variation when used in two environments, and generates an imaging blur in a certain environment, thereby reducing the resolution.

vdi≤25；

where vdi is the dispersion coefficient of the i-th lens under d-light.

A certain lens in the optical imaging system 10 satisfies the conditional expression, which is beneficial to correcting chromatic aberration and improving the color saturation of the optical imaging system 10 during imaging.

3.5<Imgh/epd≤5.2；

where Imgh is an image height corresponding to the maximum field angle of the optical imaging system 10, and epd is an entrance pupil diameter of the optical imaging system 10.

By satisfying the conditional expression, the image surface brightness is promoted when the large target surface is imaged. When the upper limit of the conditional expression is exceeded, the diameter of the entrance pupil of the optical imaging system 10 is smaller, the width of a beam of rays incident into the optical imaging system 10 is reduced, and the brightness of the image plane S17 is not favorably improved; if the lower limit of the conditional expression is exceeded, the area of the image plane S17 of the optical imaging system 10 is small, and the field angle range of the optical imaging system 10 is narrowed.

1mm^-1<tan(1/2*FOV)/f＜3mm^-1；

where FOV is the maximum field angle of the optical imaging system 10 and f is the focal length of the optical imaging system 10.

By satisfying the limitation of the conditional expression, the control of the distortion of the edge field of view of the large-angle optical imaging system 10 is facilitated, the image plane deformation is avoided, and the discrimination precision of the system is improved. When the conditional limit is exceeded, the edge distortion control of the optical imaging system 10 at large angle imaging is not facilitated, resulting in reduced imaging quality.

First embodiment

Referring to fig. 1 and fig. 2, the optical imaging system 10 of the first embodiment includes, in order from an object side to an image side, a first lens L1 with negative bending force, a second lens L2 with negative bending force, a third lens L3 with positive bending force, a fourth lens L4 with positive bending force, a fifth lens L5 with positive bending force, a sixth lens L6 with negative bending force, and a seventh lens L7 with positive bending force. The fifth lens L5 and the sixth lens L6 are of a cemented structure, and the fifth lens L5 and the sixth lens L6 have a positive bending force as a whole.

The object-side surface S1 of the first lens element L1 is convex along the optical axis, and the image-side surface S2 is concave along the optical axis; the object-side surface S3 of the second lens element L2 is concave along the optical axis, and the image-side surface S4 is concave along the optical axis; the object-side surface S5 of the third lens element L3 is convex along the optical axis, and the image-side surface S6 is convex along the optical axis; the object-side surface S7 of the fourth lens element L4 is convex along the optical axis, and the image-side surface S8 is concave along the optical axis; the object-side surface S9 of the fifth lens element L5 is convex along the optical axis, and the image-side surface S10 is convex along the optical axis; the object-side surface S11 of the sixth lens element L6 is concave along the optical axis, and the image-side surface S12 is convex along the optical axis; the object-side surface S13 of the seventh lens element L7 is convex along the optical axis, and the image-side surface S14 is convex along the optical axis.

Further, the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, and the seventh lens L7 are all made of glass and are spherical mirrors.

Further, the stop STO is disposed between the fourth lens L4 and the fifth lens L5.

Further, the optical imaging system 10 further includes a protective glass L8 disposed between the image side surface S14 and the image surface S17 of the seventh lens L7.

Fig. 2 is a spherical aberration (mm), astigmatism (mm), and distortion map (%) of the optical imaging system 10 in the first embodiment, in which the astigmatism map and the distortion map are data maps at a reference wavelength of 750.000 nm.

The reference wavelength in the first embodiment is 750.000nm, and the optical imaging system 10 in the first embodiment satisfies the conditions of the following table.

TABLE 1

It should be noted that f is the focal length of the optical imaging system 10, FNO is the f-number of the optical imaging system 10, and FOV is the maximum field angle of the optical imaging system 10.

Second embodiment

Referring to fig. 3 and 4, the optical imaging system 10 of the second embodiment includes, in order from an object side to an image side, a first lens L1 with negative refractive power, a second lens L2 with negative refractive power, a third lens L3 with positive refractive power, a fourth lens L4 with positive refractive power, a fifth lens L5 with positive refractive power, a sixth lens L6 with negative refractive power, and a seventh lens L7 with positive refractive power. The fifth lens L5 and the sixth lens L6 are of a cemented structure, and the fifth lens L5 and the sixth lens L6 have a positive bending force as a whole.

Further, the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, and the seventh lens L7 are all made of glass and are all spherical lenses.

Fig. 4 is a spherical aberration (mm), astigmatism (mm), and distortion map (%) of the optical imaging system 10 in the second embodiment, in which the astigmatism map and the distortion map are data maps at a reference wavelength of 750.000 nm.

The reference wavelength in the second embodiment is 750.000nm, and the optical imaging system 10 in the second embodiment satisfies the conditions of the following table.

TABLE 2

Third embodiment

Referring to fig. 5 and fig. 6, the optical imaging system 10 of the third embodiment includes, in order from the object side to the image side, a first lens L1 with negative refractive power, a second lens L2 with negative refractive power, a third lens L3 with positive refractive power, a fourth lens L4 with positive refractive power, a fifth lens L5 with positive refractive power, a sixth lens L6 with negative refractive power, and a seventh lens L7 with positive refractive power. The fifth lens L5 and the sixth lens L6 are of a cemented structure, and the fifth lens L5 and the sixth lens L6 have a positive bending force as a whole.

Fig. 6 is a spherical aberration (mm), astigmatism (mm), and distortion map (%) of the optical imaging system 10 in the third embodiment, in which the astigmatism map and the distortion map are data maps at a reference wavelength of 750.000 nm.

The reference wavelength in the third embodiment is 750.000nm, and the optical imaging system 10 in the third embodiment satisfies the conditions of the following table.

TABLE 3

Fourth embodiment

Referring to fig. 7 and 8, the optical imaging system 10 of the fourth embodiment includes, in order from an object side to an image side, a first lens L1 with negative refractive power, a second lens L2 with negative refractive power, a third lens L3 with positive refractive power, a fourth lens L4 with positive refractive power, a fifth lens L5 with positive refractive power, a sixth lens L6 with negative refractive power, and a seventh lens L7 with positive refractive power. The fifth lens L5 and the sixth lens L6 are of a cemented structure, and the fifth lens L5 and the sixth lens L6 have a positive bending force as a whole.

The object-side surface S1 of the first lens element L1 is convex along the optical axis, and the image-side surface S2 is concave along the optical axis; the object-side surface S3 of the second lens element L2 is concave along the optical axis, and the image-side surface S4 is concave along the optical axis; the object-side surface S5 of the third lens element L3 is convex along the optical axis, and the image-side surface S6 is convex along the optical axis; the object-side surface S7 of the fourth lens element L4 is convex and the image-side surface S8 is planar; the object-side surface S9 of the fifth lens element L5 is convex along the optical axis, and the image-side surface S10 is convex along the optical axis; the object-side surface S11 of the sixth lens element L6 is concave along the optical axis, and the image-side surface S12 is convex along the optical axis; the object-side surface S13 of the seventh lens element L7 is convex along the optical axis, and the image-side surface S14 is convex along the optical axis.

Fig. 8 is a spherical aberration (mm), astigmatism (mm), and distortion map (%) of the optical imaging system 10 in the fourth embodiment, in which the astigmatism map and the distortion map are data maps at a reference wavelength of 750.000 nm.

The reference wavelength in the fourth embodiment is 750.000nm, and the optical imaging system 10 in the fourth embodiment satisfies the conditions of the following table.

TABLE 4

Fifth embodiment

Referring to fig. 9 and 10, the optical imaging system 10 of the fifth embodiment includes, in order from an object side to an image side, a first lens L1 with negative refractive power, a second lens L2 with negative refractive power, a third lens L3 with positive refractive power, a fourth lens L4 with positive refractive power, a fifth lens L5 with positive refractive power, a sixth lens L6 with negative refractive power, and a seventh lens L7 with positive refractive power. The fifth lens L5 and the sixth lens L6 are of a cemented structure, and the fifth lens L5 and the sixth lens L6 have a positive bending force as a whole.

Fig. 10 is a spherical aberration (mm), astigmatism (mm), and distortion map (%) of the optical imaging system 10 in the fifth embodiment, in which the astigmatism map and the distortion map are data maps at a reference wavelength of 750.000 nm.

The reference wavelength in the fifth embodiment is 750.000nm, and the optical imaging system 10 in the fifth embodiment satisfies the conditions of the following table.

TABLE 5

Table 6 shows values of f56/f, f7/f, f1/CT1, R3/CT2, f23/f, TTL/EPL, Imgh/epd, and tan (1/2 × FOV)/f in the optical imaging systems 10 of the first to fifth embodiments.

Table 7 shows values of 1/(n486-n950) of the first lens to the seventh lens in the optical imaging system 10 of the first embodiment to the fifth embodiment.

	First embodiment	Second embodiment	Third embodiment	Fourth embodiment	Fifth embodiment
						First lens	27.90	27.90	27.90	27.90	27.90
Second lens	12.13	12.13	12.13	12.13	12.13
						Third lens	30.59	30.59	30.59	30.59	30.59
Fourth lens	12.13	12.13	12.13	12.13	12.13
						Fifth lens element	37.83	37.83	37.83	37.83	37.83
Sixth lens element	13.05	13.05	13.05	13.05	13.05
						Seventh lens element	46.40	46.40	46.40	46.40	46.40

Referring to fig. 11, an image capturing module 100 according to an embodiment of the present invention includes an optical imaging system 10 and a photosensitive element 20, wherein the photosensitive element 20 is disposed on an image side of the optical imaging system 10.

Specifically, the photosensitive element 20 may be a Complementary Metal Oxide Semiconductor (CMOS) image sensor or a Charge-coupled Device (CCD).

The utility model discloses get for instance module 100 includes optical imaging system 10, optical imaging system 10 is through the configuration reasonable to the curved power of inner lens to the combination focus scope of fifth lens L5 and sixth lens L6 has been injectd, has satisfied getting for instance module 100 to the confocal demand of formation of image of day night. The image capturing module 100 also has better imaging capability in dark environments such as night, tunnel, mine hole, underground parking lot and the like through the optical imaging system 10.

Referring to fig. 12, an electronic device 200 according to an embodiment of the present invention includes a housing 210 and an image capturing module 100, wherein the image capturing module 100 is mounted on the housing 210.

The electronic device 200 of the embodiment of the present invention includes but is not limited to an electronic device supporting imaging, such as a smart phone, a tablet computer, a notebook computer, an electronic book reader, a Portable Multimedia Player (PMP), a portable phone, a video phone, a digital still camera, a mobile medical device, and a wearable device.

The utility model discloses electronic device 200 includes getting for instance module 100, through the configuration of reasonable zigzag power, can promote the formation of image quality of optical imaging system 10, has realized the confocal demand of formation of image of electronic device 200 day night, makes it in the darker environment of light such as night, tunnel, mine opening, underground parking garage, also can have better formation of image ability.

Referring to fig. 13, a mobile device 300 according to an embodiment of the present invention includes a body 310 and an image capturing module 100, wherein the image capturing module 100 is mounted on the body 310.

The utility model discloses mobile device 300 includes but is not limited to for vehicle that can manual drive or automatic traveling such as minibus, motorbus, large truck, fork truck, bulldozer.

The utility model discloses mobile device 300 includes gets for instance module 100, through the configuration of reasonable zigzag power, can promote the formation of image quality of optical imaging system 10, has realized mobile device 300 to the confocal demand of formation of image of day night, makes it in the darker environment of light such as night, tunnel, mine opening, underground parking garage, also can have better formation of image ability.

It is obvious to a person skilled in the art that the invention is not restricted to details of the above-described exemplary embodiments, but that it can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. An optical imaging system, comprising, in order from an object side to an image side:

a fourth lens having a positive refracting power;

a fifth lens having a positive refracting power;

the optical imaging system satisfies the following conditional expression:

6<f56/f<10；

2. The optical imaging system of claim 1, wherein an image side surface of the fifth lens is cemented to an object side surface of the sixth lens;

3. The optical imaging system of claim 1, wherein an operating wavelength band of the optical imaging system comprises 0.4 μ ι η to 1 μ ι η.

4. The optical imaging system of claim 1, wherein the optical imaging system satisfies the following conditional expression:

4<f7/f<7；

5. The optical imaging system of claim 1, wherein the optical imaging system satisfies the following conditional expression:

-7<f1/CT1<-3；

6. The optical imaging system of claim 1, wherein the optical imaging system satisfies the following conditional expression:

-8<R3/CT2<-2；

7. The optical imaging system of claim 1, wherein the optical imaging system satisfies the following conditional expression:

-12<f23/f<-6；

8. The optical imaging system of claim 1, wherein the optical imaging system satisfies the following conditional expression:

1.5<TTL/EPL<3.5；

9. The optical imaging system of claim 1, wherein at least one lens in the optical imaging system satisfies the following conditional expression:

1/(n486-n950)≤30；

10. The optical imaging system of claim 1, wherein at least one lens in the optical imaging system satisfies the following conditional expression:

vdi≤25；

wherein vdi is an abbe number of the at least one lens.

11. The optical imaging system of claim 1, wherein the optical imaging system satisfies the following conditional expression:

3.5<Imgh/epd≤5.2；

12. The optical imaging system of claim 1, wherein the optical imaging system satisfies the following conditional expression:

1mm^-1<tan(1/2*FOV)/f＜3mm^-1；

13. An image capturing module, comprising:

the optical imaging system of any one of claims 1 to 12; and

the photosensitive element is arranged on the image side of the optical imaging system.

14. An electronic device, comprising:

a housing; and

the image capturing module of claim 13, wherein the image capturing module is mounted on the housing.

15. A mobile device, comprising:

a body, and

the image capturing module as claimed in claim 13, wherein the image capturing module is mounted on the body.